Energy and exergy-based working fluid selection for organic Rankine cycle recovering waste heat from high temperature solid oxide fuel cell and gas turbine hybrid systems

This paper performed a comparative analysis of organic Rankine cycle (ORC) using different working fluids, in order to recover waste heat from a solid oxide fuel cell-gas turbine hybrid power cycle. Depending on operating parameters, criteria for the choice of the working fluid were identified. Results reveal that due to a significant temperature glide of the exhaust gas, the actual ORC cycle thermal efficiency strongly depends on the turbine inlet temperature, exhaust gas temperature, and fluid's critical point temperature. When exhaust gas temperature varies in the range of 500K to 600K, R123 is preferred among the nine dry typical organic fluids because of the highest and most stabilized mean thermal efficiency under wide operating conditions and its reasonable condensing pressure and turbine outlet specific volume, which in turn results in a feasible ORC cycle for practical concerns. Copyright (c) 2012 John Wiley & Sons, Ltd.